The present invention relates to an alignment device for mounting an alignable part, such as a thermal printhead, on a support frame that can be independently guided to position the working component in a mounting housing structure. The alignment device provides for precise alignment of a line on the working part, such as a print line of thermal print elements, relative to close fitting guides on the support frame so when put into use the working component is guided into its proper location. Proper alignment of thermal printheads, in particular, as well as other working components that have a narrow line of contact with another element is critical to satisfactory operation.
Conventional thermal printheads are held by a variety of different types of supports. In particular since printheads must be moved for servicing ribbons, pivoting frames are used for moving the printheads between a working and an open position. The printhead is pivoted 90.degree. away from the platen used with the printhead. Obtaining accurate alignment of the printhead when moved back into working position relative to the platen has been a problem.
Also, in the copending application cross referenced above, a structure for supporting the printhead so that it will remain oriented in space as it is moved to open position to keep the print line facing away from operators provides for pivotal mounting of the support for the printhead. The support or frame is guided directly onto the shaft of a platen roller. If the print line is oriented properly with the guides carried on the support mounting frame, the print line will be properly oriented relative to the platen during use.